Lighting systems are commonly used for aesthetic purposes around residences and businesses. Security lighting systems are also commonly used to monitor residential and business properties during nighttime hours. The illumination provided by these lighting systems can provide a certain element of security at night. Such lighting systems may be controlled by a mechanical or electronic timer so that the lighting system is turned on for selected periods of time, such as during hours of darkness. The timer automatically turns the lighting on and off at specific times when a building is unoccupied to give the impression that people are present within the building. One disadvantage to the use of a timer is the precision by which it operates. If the lights are turned off at the same precise time over a period of days, a potential intruder might conclude that the building is unoccupied.
In addition, many conventional timers are motor driven and based on a twenty-four hour period. The current required for the motor drive may prevent the use of battery backup. As a result, a loss of power will shift the control system's timing mechanism forward, and the change in timing may cause the lighting to turn on at improper times, which may dispel the desired impression of occupancy.
Other systems for lighting control use photosensors in so-called dusk-to-dawn control systems, which are configured to turn lights on and off based upon the presence (or absence) of daylight. These systems are primarily designed to keep the perimeter of a building illuminated constantly, and are not intended to give an impression of building occupancy. Also, because the lights will remain illuminated all night, the energy consumption is greater than that which would be required for an illumination period lasting from one third to one half of the night time.
Another method of controlling a lighting system uses a motion detector capable of turning on the light when movement is detected. A motion detector may use a variety of methods of detecting movement including infrared or sound. The motion detector may be activated to switch on a light upon the detection of motion. Activation of the motion detector by an individual entering into the monitored area, turns on the light to illuminate the area for a period of time. However, there may be significant amounts of normal activity during the early evening hours that could repeatedly trip the motion detector and undesirably activate the lighting system.